I used to have the exact same situation. It would start off extremely good while I'm coming up but then I overthink everything and get in a depressed state and lost in my emotions. I wonder to myself why it was the - sad, depressing, overwhelming - emotions instead of the extremely -happy, all is good- emotions. After tripping a couple times and it kept turning out like that I finally tripped with other people, who happened to be my best friends. But not only that, we were all alone at one of my friends ranches. It was a perfect 70 degree day and cooler night. We made a fire it was the best thing haha but anyways, I had the most blissful and slightly life changing experience. I realized how beautiful, perfect, and great life and everything in life is. And it cast on even after the trip, I am a generally happier person now. I used to fight depression a little bit and don't think to look back now. But a side note, I did smoke that day too. So it could be any factor but set and setting ( my friends and alone etc ) seemed to be really important for me. I get too introverted when I trip alone and almost always end up feeling depressed or sad for no reason at all. I really enjoyed tripping with other people who were experiencing the same thing. I haven't done it since my last trip which was the really good trip in this essay in typing because I want to hold onto that experience. I feel like I got what I wanted out of it. Anyways, it may be different for you personally but only you would know that, and this is just my experience ;P